This description of related art is provided for the purpose of generally presenting a context for the disclosure that follows. Unless indicated otherwise herein, concepts described in this section are not prior art to this disclosure and are not admitted to be prior art by inclusion herein.
Many computing and electronic devices include a transceiver to facilitate communication over a wireless network or directly with other devices. To increase the available capacity of wireless bandwidth, additional bands of spectrum have been allocated for wireless access networks. To use these additional bands, integrated circuit transceivers are designed to have tunable circuits that cover an increasingly wider frequency range in various RF circuits, such as a voltage-controlled oscillator (VCO) or a front-end filter.
Covering the wide frequency range of cellular radio bands involves using multiple VCOs, which consume a large amount of power and die area of an integrated circuit. Conventional approaches to widen the tuning range of a single VCO in a transceiver can lead to a degradation of phase noise or an increase in power consumption by the VCO, as well as occupying an even larger area on an integrated circuit. Some of the conventional approaches for handling wide frequency ranges are based on dual-mode resonance tanks that employ a switched-inductor. These approaches, however, lead to a poor inductor Q (quality factor) for one mode of oscillation (e.g., the higher resonance frequency). Consequently, the phase noise of the VCO increases in the frequency band with the poor-Q inductor, which reduces the performance of the transceiver in that frequency band.